AR15 Rifle -vs- M4 Carbine??

[NYH1]

I'm just wondering. The full size (20" barrel) AR15 is the civilian version of the M16 rifle. Does that mean a shorter carbine size (16" barrel) AR15 is the civilian version of the M4 carbine? I guess what I'm asking is what makes a civilian version M4 carbine?

Thanks, NYH1.

 

[conhntr]

The chart!!!!

 

[NYH1]

Chart???

 

[NYH1]

I have a Stag Model 1 with a 16" barrel and the plus package, the spec's are below. Is mine a considered a civilian version of the M4, or just a short barreled AR15?

Bolt & Bolt Carrier
Bolt Material- Carpenter 158, shot peened (fixture method).
HPT bolt (100%) HPT bolt round M197 or SAAMI equivalent.
MPI bolt (100%), MPI bolt rejection- cracks & inclusions.
Spring Extractor 5.
Extractor Spring Buffer- black.
Shrouded Full Circle M16 Carrier, side staked carrier key.

Barrel & Upper Receiver
Barrel Steel- 4150.
HPT barrel (100%).
HPT barrel round- SAAMI equivalent to M197.
MPI barrel (100%).
MPI barrel rejection- cracks & inclusions.
Chamber- 5.56.
1 in 7 twist rate, chrome lining barrel & chamber.
Barrel Feedramps- M4 extended.
Upper Feedramps- before anodizing.
FSB- "F", FSB Pins- taper pins, Finish Under FSB- yes.
Heat Shields- double.

Lower
R.E. Diameter- 1.14", R.E.
Material- 7000 series.
Castle Nut- staking,
Buffer- H (3.6 oz)

I ordered mine with the A2 Buttstock.

Thanks, NYH1.

 

[NG VI]

The M16 and M4 rifles are AR-type, but they are a specific setup made by specific manufacturers who have contracts to supply them.

Any other AR-type rifle is an AR-15 of whatever build and specifications. They aren't versions of the M16 or M4.

 

[Onmilo]

People get all twitchy about materials and specifications.
No civilian legal semi-auto is truely mil-spec because they are missing the most important components that make a weapon "Mil_Spec", the happy switch and auto sear.

A true civilian legal M4 carbine will have a 14.5" barrel legally registered as a short barrel rifle where allowed, or a 14.5" barrel with a 1.75" flash suppressor welded and pinned.

In my humble opinion 16" barrels are somewhat ridiculous.

 

[CharlieDeltaJuliet]

A lot of companies list them as just "carbines" or "M4 Carbine profile". Onmilo is absolutly correct about the specifications of them. The true M4 is a 14.5" barrel.

 

[jmr40]

In my humble opinion 16" barrels are somewhat ridiculous.

I like the 16" barrel for a lot of uses. The M-forgeries as they are referred to have no real use for civilians. A 16" barrel without the cutout for the grenade launcher and with a midlength gas system make much more sense. The 16" barrel is a good choice and the legal minimum for most folks in a SD rifle, but how many civilains can use a grenade launcher. The neat thing about AR's is the versatility. If you want or need more barrel you can build it anyway you want.

 

[Destructo6]

The Colt 6920 is the closest, for better or worse, to the Colt M4 without getting into NFA territory.

 

[Quentin]

The Colt 6920 is the closest, for better or worse, to the Colt M4 without getting into NFA territory.

Very true. And if the barrel was cut to 14.5" the upper part of the carbine would be identical to the military version though to be civilian legal the flash hider would need to be pinned.

The civilian 6920 lower of course is semiauto not semiauto/burst.

 

[coolluke01]

In my humble opinion 16" barrels are somewhat ridiculous.

I'm certainly not taking offense to this statement as you said it was opinion.

I have the 16" AR; and I like it very much. I researched barrel length at, well, length. There is no accuracy gain in the longer barrel! You do gain a velocity though. About 300fps or 10%. Hardly worth the added length and weight if you ask me. If I were doing long range hunting 400+ yards, then I would consider it helpful. But there are better rounds for that distance so I think it's a moot point. Bigger isn't always better.

 

[HDCamel]

but how many civilains can use a grenade launcher

Well, they're not illegal, just expensive.

Regardless, you can also get one of those 30mm flare guns.

 

[Pete D.]

20"

There is no accuracy gain in the longer barrel! You do gain a velocity though. About 300fps or 10%. Hardly worth the added length and weight if you ask me. If I were doing long range hunting 400+ yards, then I would consider it helpful. But there are better rounds for that distance so I think it's a moot point. Bigger isn't always better.

Sure about that "no accuracy gain" comment? Inherent accuracy...maybe. Field accuracy....using iron sights, the longer sight radius of the 20" barrel allows for greater aiming precision at pretty much any distance. Target shooters, for example, tend to make their barrels longer, not shorter.
About the weight and length.....how much extra does four inches of barrel weigh that it would be a burden? Same applies to adding four inches....for most purposes, what problem is there? Seems like a bargain for a 10% velocity gain.

 

[W.E.G.]

The 20" version is the one you shoot on the National Match Course, and out to 600 yards competitively.

The 16" (and shorter) version is the one you shoot on the pistol range.

At least that's been my observation of how it usually goes among the hobby shooters who own such things.

Colt is now marking all their 16" models "M4."
Even though they aren't a "true" M4.

 

[Harley Rider 55]

My 16" DD M4 is 'yote accurate. That's well within specs of it's intended use. Prarie dogs? My Remington 700 in .204 Ruger.

Today's quality M4 carbines are as accurate (for the intended targets) as the old 20" military rifles. Today's 20" rifles are silly accurate and prarie dog accurate at 400 yards.

 

[CraigC]

My 16" kills coyotes just fine.

 

[Welding Rod]

In most basic terms, the flat top reciever differentiates the AR15 carbine from the commercial M4 clone.

Then there is a list of specifics you have already posted above.

 

[EMS_92]

Like others have said all M4s and M16s are AR15s, just built a certain way.

 

[HDCamel]

There are other things to consider in the 20" vs 16" argument though.

For starters, while there's no real change in theoretical accuracy, the longer sight radius of a full-length rifle aids in practical accuracy with iron sights as well as allowing you to mount low-power optics further away (to increase your field of view).
Also, I personally find full-length rifles to have better balance, which makes the gun feel more stable (easier to keep on target) if slightly less pointable (easier to place on target).
Furthermore, full-length rifles are softer shooters both from the added weight and the less violent cycling action due to the full-length, lower pressure gas system.
Add in that the AR-15 is typically most reliable in it's full-length form AND it still enjoys ALL of the customization options available to the carbines (if not more) and I say that the extra 1.5-2 lbs. is a more than worthwhile sacrifice.

That extra 300fps is just icing on the cake.

 

[coolluke01]

Sure about that "no accuracy gain" comment? Inherent accuracy...maybe. Field accuracy....using iron sights, the longer sight radius of the 20" barrel allows for greater aiming precision at pretty much any distance. Target shooters, for example, tend to make their barrels longer, not shorter.

That's a pretty big if. I don't know anyone who is talking about accuracy in a 16" or 20" barrel for 400-500 yards that isn't using a scope.
Yes you are right that longer sight radius does help, but the difference between 16" and 20" for that is even negligible.

About the weight and length.....how much extra does four inches of barrel weigh that it would be a burden? Same applies to adding four inches....for most purposes, what problem is there? Seems like a bargain for a 10% velocity gain.

I guess my decision was based on the fact that I wanted a bull barrel and still wanted to be able to walk around the woods with it. That 4" makes a difference.

 

[NG VI]

I think what I wanted to say is that you are approaching it backwards, there is no non-government version of the M16 or the M4, but all M16s and M4s are government versions of the AR-15, built in a specific way with specific parts and features that may or may not be in common with any given commercial AR-15 rifle.

 

[76shuvlinoff]

The Colt 6920 is the closest, for better or worse, to the Colt M4 without getting into NFA territory.

hmmm says M4 on it. Someone is fibbing to sell guns? Say it ain't so!!

 

[Onmilo]

I haven't experience any real practical accuracy difference between 20" chrome lined Mil-spec barrels and 14.5" or 16" chrome lined mil-spec type barrels. I own rifles with all three in 1-7" and 1-9" twist rates.

If you were to compare a true match grade 16" stainless steel barrel to a true match grade 20" stainless steel barrel rifles with a 1-7" or 1-8" twist using heavy match bullets and shooting at 600 meters, I believe the average shooter will find a very slight edge in favor of the 20" barrel simply due to a slight gain in velocity and bullet stability.

If you shoot off a bench at 100-200 meters as a rule, you will definately see an accuracy gain using a stainless steel match grade barrel in either length.

 

[CountryUgly]

Not sure what mine is? Upper is a Colt 14.5" (PA flashhider of course) w/ FA BCG. Lower is a Spikes Zombie Edition with a 3 position switch and hyd. buffer. I am lacking "Fun Mode sear" and I don't think they use Spikes in the sand box but I'll be happy even if "mall ninjas" call my pea shooter a "poser". Accuracy is MOA'ish, reliabilty isn't even a question. It may not be Mil-Spec but it'll handle any "war" I care to wage on the range or in a "dogtown".

 

[Eb1]

I have a 16" HF FN 1:7 twist barrel with MOE Rifle length hand guards. I can easily put 55 grain soft points or 55 grain FMJ on target at 540 yards. Past that with 55 grain bullets it is tough to hit consistently.

Now move to 69 grain SMK or 75 grain Hornady Match, not the Amax, and I can hit 600 yards easily with decent scores, and the 540 yards groups become around 3" or less.

Now take my WOA 1:7 stainless upper tha is 20", and well, the scores go way, way up at 600 yards with anything from 62 grain to 77 grain. The 20" is just a better rifle while my disapator is a better, well shorter rifle that shoots very good to 540 yards. You wouldn't think that 60 yards and 4" of barrel would do that to ya, but it does.

Also when using a dissapator you do not have the disadvantage of a short sight radius. I wouldn't trade my PSA Dissy for any AR-15. It is dead on with A2 sights, and is easy to throw around. It also wears an A2 butt stock. I don't care for hose adjustable stocks.